Recall 21V328 affects 13 2021 Peterbilt 579 and 348 trucks for incorrect spring brake chamber springs. Free repair at any franchised Peterbilt dealer once available.
Peterbilt is recalling 13 2021 579 and 348 trucks because the spring brake chamber was built with incorrect springs that can let the pressure plate shift. A torn diaphragm can cause loss of air pressure and increase crash risk, and the Peterbilt dealer repair will be free once available.
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What's wrong?
The spring brake chamber on 2021 Peterbilt 579 and 348 trucks is part of the air brake assembly. It uses air pressure and a heavy internal spring to hold or release brake force, including the park brake. The chamber has to keep the spring, pressure plate, and diaphragm lined up so air pressure moves the brake parts the right way.
On these trucks, some brake chambers were built with springs that were out of specification. The spring was deformed after heat treatment, and that misalignment lets the pressure plate shift inside the chamber. Over use, the shifted plate wears into the diaphragm, the flexible seal that holds air pressure, and creates a fatigue hole.
Drivers can notice low air warnings, trouble getting the truck into gear because air pressure is low, audible air leaks, or failure to build enough pressure to release the park brakes. Those are warning signs that the brake chamber is losing air pressure.
Who's affected?
The 579 and 348 model lines both involve the ADB brake assembly, with brake chamber and air brake listings under the brake system.
| 2021 Peterbilt 579 | brake system |
|---|---|
| 2021 Peterbilt 579 | brake system |
| 2021 Peterbilt 348 | brake system |
| 2021 Peterbilt 348 | brake system |
| Units affected | 13 |
| Field incidents | NHTSA has logged 52 field incidents to date. |
The year and model narrow the scope, but the VIN decides. Check your VIN to confirm whether your specific truck is included.
What's the safety risk?
A torn diaphragm can cause air-pressure loss, which increases crash risk. Watch for low-air warnings, audible air leaks, trouble getting into gear, or park brakes that will not release because the system is not building enough pressure. Schedule the repair soon and treat any air-pressure warning as a reason to call the dealer. Repair will be free at any franchised Peterbilt dealer once available.
What should I do?
- Check your VIN to confirm your 2021 Peterbilt 579 or 348 is included in this recall.
- Wait for Peterbilt remedy instructions before scheduling the brake-chamber replacement.
- Contact a franchised Peterbilt dealer when the remedy opens to schedule the free brake-chamber replacement that fixes the out-of-spec spring brake chambers.
- Reference recall number 21V328 and Peterbilt recall 21PBE when you call.
- Avoid driving if the truck shows brake air-pressure loss; arrange service before returning it to work.
What happens at the repair
The final dealer repair is still listed as under development, so do not assume it can be scheduled as a completed recall repair yet. Once Peterbilt opens the remedy, a Peterbilt technician will replace the brake chambers affected by the incorrect spring assembly. Parts and labor will be free under the recall. Peterbilt has a general reimbursement plan on file for documented out-of-pocket repairs tied to this defect. Keep repair paperwork for the reimbursement claim and ask the service desk how Peterbilt handles submission.
| Reimbursement | Reimbursement available |
|---|
Timeline
| May 10, 2021 | NHTSA published the recall |
|---|---|
| July 9, 2021 | Dealer notification began |
| July 9, 2021 | Dealer notification ended |
| July 9, 2021 | Owner notification mailed |
| July 9, 2021 | Interim owner notification (was planned for this date) |
Frequently asked questions
What is recall 21V328?
Recall 21V328 covers 13 2021 Peterbilt 579 and 348 vehicles with spring brake chambers assembled with incorrect springs. The pressure plate can shift, tear the diaphragm, cause air pressure loss, and increase crash risk. Peterbilt's dealer remedy is brake chamber replacement free of charge.
What should I do if my 2021 Peterbilt 579 or 348 is on this recall?
Check your VIN to confirm your specific truck is included in recall 21V328. If it is, contact a franchised Peterbilt dealer and ask for the brake chamber replacement. Reference recall 21V328 and Peterbilt recall number 21PBE when you call.
Is the recall repair free?
Yes. Federal recall law requires the manufacturer to perform the recall repair at no cost. For this recall, Peterbilt dealers will replace the affected brake chambers free of charge.
What is the safety risk?
The safety risk is loss of air pressure in the brake system. If the pressure plate tears the diaphragm, the truck can lose air pressure, which increases crash risk. Confirm your VIN, then arrange the free brake chamber replacement with a Peterbilt dealer.
When were owners notified about this recall?
Peterbilt mailed owner notification letters on July 9, 2021. If you bought the truck used or never received a letter, the VIN still decides whether recall 21V328 applies. You can also call Peterbilt customer service at 1-940-591-4220.
More information
| NHTSA campaign page | nhtsa.gov/vehicle-recalls/21V328000 |
|---|---|
| Peterbilt customer service | 1-940-591-4220 |
| NHTSA recall # | 21V328 |
| NHTSA recall # (full) | 21V328000 |
Source documents
-
Download Recall Document (PDF) (PDF) - Download Quarterly Report (PDF)
- Download Recall Document (PDF) (PDF)
- Download Owner Notification Letter (PDF)
- Download Recall Report (PDF)
- Download Recall Acknowledgement (PDF)
This article is generated from NHTSA's primary recall filings and reviewed against the source on May 23, 2026. RecallNotify does not paraphrase NHTSA's consequence language; that text is reproduced as written above. Editorial standards →